Capacity controlled textile press



Feb. 26, 1946. G. c. DEVOL, JR., ET AL 2,395,780

CAPACITY CONTROLLED TEXTILE PRESS '7 Sheets-Sheet 1 1 N VENTORS 5 H 8 0 JA m 1% 0 in M .YTE A 5 W w? 9% K mum nrwm N Om n rw WQL A 55 u m 5 7"Sheets-Sheet 2 m/suLA T/ON $501? an? a.

EEK/A RD ELEERY' Feb. 26, 1946. s c. DEVOL. JR, ET AL CAPACITY CONTROLLED TEXTILE PRESS Filed Sept. 28, 1959 Feb. 26, 1946. G. c. DEVOL, JR, ET AL ,780

CAPACITY CONTROLLED TEXTILE PRESS Filed Sept 28, 1939 7 Sheets-Sheet 4 UJJ m4 /94 w in J [97 'ma'asm wa e: 'qaaaxww I77 4 za ylllla will 5 178 I9) 1 76 j /i /z 15p, 9 'yt 206 F ATTOR EYS Fb. 26,1946. G. c. DEVOL. JR.; ETAL 2,395,730

' UAPACITY CONTROLLED TEXTILE PRESS Filed Sept. 28, 1939 7 Sheets-Sheet 5 INVENTOR GEORGE C. EDWARD ELBERT .SHERMAN BYfl LW vial/4m ATTORN EYS UEl/OL J PRI7CHH D Feb. 26, 1946. e. c. DEVOL, JR., ET AL 2,395,780

CAPACITY CONTROLLED TEXTILE PRESS Filed Sept. 28, 1939 7- Sheets-Sheet 6' l l I I i I II 308 g; /200 l u ll I, I

INVENTORS BY I KW ATTORNEYS Feb. 26, 1946. G. c. DEVOL, JR. ETAL 2,395,780

CAPACITY CONTROLLED TEXTILE PRESS Filed Sept. 28 1939 7 Sheets-Sheet 7 I N VE NTORS nun-AA Allllllll IIVIV'II """VIIIV" All P RQN wwwN BY ELBERT SHERMAN guild I i ATTORNEYS Patented Feb. 26, 1946 CAPACITY CONTROLLED TEXTILE PRESS George C. Dcvol, Jr., Edward M. Pritchard, and Elbert W. Sherman, Flushing, N. Y., assignors to The Prosperity Company, Inc., Syracuse, N. Y., a corporation of New York Application September 28, 1939, Serial No. 296,926

13 Claims. (CI. 3840) This invention relates to power-operated pressing machines, and more particularly to a capacity controlled textile press.

Conventional laundry-ironing presses used in commercial laundries and the like, also other types of textile presses of a variety of uses, are ordinarily of the jaw-motion type having coacting pressing members usually called the "head and "buck which open and close on the work. These presses are usually power driven, that is, they are closed and held closed by motor means which subjects the work to a high degree of ironing or finishing pressure under heat. One or both pressing jaws (head and buck) are heated, usually by steam, for ironing and finishing the damp laundered work smoothly laid upon the buck.

The conditions and manner of use. with other special requirements and problems met in the textile ironing or smoothing art, comprising the laundry trade, the tailoring trade, and the clothing manufacturing industry, have come to widely distinguish the textile and apparel presses as a general class from other pressing fields.

The upper pressing head of a conventional laundry-ironing press has a metallic plated or polished surface to impart a smooth firm finish to the damp work being pressure-ironed and dried. On the other hand, the upper pressing head of a conventional garment press usually has a cloth covered surface to aid in distributing a spray of steam applied to the dry woolen garment to dampen it for finishing purposes. The lower buck of each type of press has a padded surface acting as a yielding bed on which to eiiectively iron the work, which is damp-when it reaches the press, in the case of laundry work, and dry in the case of garment work. The ironing pad on each type of press permits the buttons, seams, and other irregularities to be depressed into the buck to equalize the pressure of the head around these parts of the work, as the head seals down and is maintained under final heavy-ironing pressure until the work is ironed dry and finished.

At the present stage of the art, the operation of the motor means of conventional laundry and other textile presses is usually governed by a twohand control comprising two safety manuals or buttons which are sufficiently spaced apart as to require an operator to simultaneously use both hands to energize the motor means and c1o:e the pressing jaws. This manual two-hand control is largely in use because of the high degree of safety it affords to th operator; it compels her to give conscious attention to the manual control of the press because of the requirement of first withdrawing her hands from the press after laying and smoothing the work on the buck, and thereafter holding both of her hands on the control buttons or handles during and until the press is 5 safely closed. Therefore, the operator must remain at the press until she fully closes it, which means a certain loss or time after she has completed th lay" of the work in one press and before she can turn to the next'press.

Also, according to present practice, either an electrically-operated or a fluid-pressure operated motor means is employed to drive laundry and other textile presses, the fiuld-pressure'or pneumatic type motor means being one of the more convenient forms of presses now largely in use. I One of the mor generally used laundry presses is sometimes referred to as the full automatic" press by reason of its movable pressing Jaw or Jaws being fully powered to close the press all the way from wide-open to fully-closed position by motor means. It is because of the dangers to an operator, inherent in a wide-openingfull automatic press, that two-hand control is now the accepted and required control means for such 5 presses, because'this type of control compels the operator to withdraw both of her hands from the buck, after completing the lay (smoothing, etc.) of the work, before she can bring the heated ironing Jaws or pressing members to finally closed position under heavy-ironing pressure.

it is an object of this invention to produce a safe power-operated textile press, not requiring two-hand control, for use in laundry-ironing work in commercial laundries and otherwise in connection with the pressure-ironing and finishing of all manner of textile materials; and more particularly it is an object to produce a new iorm of control instrumentality for such presses which does not require the operator to give his or her mental attention to the manual control means of the press, as a result 0! which the operator simply makes the lay of the work on the buck oi'onepress and turns away therefrom to attend another tween the pressing jaws, or when she bodily moves away from the press, to automatically energize the motor means to close the press and hold it closed for the duration'of the pressure-ironing period.

Thus, the approach and departure of an operator to and from her station at the press, for removing the ironed work and making the next new lay thereof, serves to automatically control the opening and closing of the press without any mental or manual attention on her part to the control mechanism of the machine.

Another object is to provide acapacity responsive control instrumentality for a press in which parts of the press act as the capacity responsive electrodes.

Also, it is an object to provide a press with a closed positions, respectively, of a portion of a press having a modified form of electrode arcapacity control therefor having an electric field 7 in the vicinity of the press (or between its pressrangement, known as the movable bar form.

Figure 8 is a sectional plan view of a second form of-electrical condenser, shown on the press in'Pigures 6 and 7: andFisurc 9 is a side view thereof.

Figure 10 is a diagrammatical plan of a plu- "rality of presses having capacity control and arranged in a group representative of a plurality of Another object is to provide an electric control for a press which operativelyv responds to the presence or absence of a bochr between the jaws of the press, the response for various positions of the movable law or laws being adjustable so as to permit the use of the same type of control mechanism with presses of diiferent designs" andshapes but'having substantially the same control, response and operating characteristics, so as to attain a standard uniformity of perform-. ance of each press making up a group of presses in a laundry or other place of use. 7 I

' Still another object is toprovide an electrical control instrumentality having its electrical fleld' closely related to the press in order that its operation be not adversely affected by the presence of the operator, or bythe presence of another operator, standing at, or in the electrical control field of an adjacent press, so that several presses may be used or operated in close proximity to each other by one or more operators.

Another object is to provide a capacity control instrumentality which may be applied to any existing press by the addition of small electrodes which are carried by thehead or buck, or both thereof, and which are insulated therefrom.

Likewise, it is an object to provide a capacity responsivecircuit for a, control instrumentality, which is extremely sensitive and hence aflords positive action in an accurately predeterminedmanner, operates with great speed so as to provide substantially instantaneous action, and is inherently safe, failure of any of the parts always causing the press to open, and more particularly, preventing it from closing in the first instance.

Other objects and advantages of our improved capacity controlled textile press will become apparent from, or be specifically referred to in,

the following description thereof written in connection with the accompanying drawings showing examples of the invention, in which:

Figure 1 ice. side view of a laundry press having our improved electrical control, comprising what we sometimes refer to as our fixed bar type or form of electrode structure, in combination with a control circuitshown diagrammatically as one form of capacity responsive means which we may refer to as our safety A. C. circuit. Figure 2 is a plan view of the movable ironing head of the press, showing the sensitive: electrode carried thereby. Figure 3 is an enlarged sectional view of a portion of the electrode, showing the manner presses adapted to be used by one or more operators.

Figure 11 is a side view of a laundry press with the head and buck insulated from the frame and ground, and with a portion of the capacity control mechanism shown atically and in section. This secondform of electrode structure may be called the insulated jaw type. Figure 12 is a cross sectional view of the ironing head or movable pressing law of Figure 11 insulated from the press frame. Figure 13 is a longitudinal sectional .view of an example of an electrically insulated steam connection or Joint for the movable ironing head.

Figure 14 is an enlarged sectional plan view of a third) example of variable condenser which may be used to maintain the electrostatic field constant in its control function and which is shown as a matter of convenience with the Press of Figure 11, and this is the telescoped-tube form thereof. Figure 15 is a cross sectional end view v preferred as a press control over the safety A. C.

circuit shown in Figin'e 1.

Construction of conventional press For the purpose of illustrating this invention, a simple or elementary form of power-operated laundry press is shown. Known types most generally employ the stationary lower buck'and movable upper ironing head, although in' some constructions both the head and buck are movable. In other instances, the buck moves in and out of registration with the stationary head. However, all textile presses are of one form or another having jaw motion. in that the work is pressed between two or more pressing jaw members. one or the'other or both of which are power operated.

The press' illustrated herein has a fram i with a work table I under the pressing laws, that is,

. under the coacting head and buck. An ironing buck or bed I is mounted stationary on the frame,

- and has the usual form of padding 4 on its ironpressing machines are manufactured in a variety of shapes and sizes best suited to particular anpard and textile materials to be pressed The press lever lifts the head I high above asoavso the buck to fully expose its padded surface to the operator while making her lay of the work, and consequently a wide opening is afforded for the convenience of the operator. This type of press, with its wide opening head, swingable up and down in relation to the buck around the rear horizontal axis 1, is sometimes called the scissors-action type of full-automatic press. It is one of the more convenient forms by which to disclose this invention.

A conventional form of power-actuating means is shown for closing and opening the press. The motor means may perform both functions. that is the opening and closing cycle, but more generally the motor means is employed to close the press and simultaneously stretch or load a spring counterbalance. whereupon the latter performs the reverse function of opening the press and holding it open. As said before, electric or other motor means may be employed, but the example shown comprises a pneumatic motor means 2 usually operated by air pressure.

The cylinder 8 is mounted to oscillate on a frame pivot i and its piston H with connecting red I! is pivotally connected at II to the head arm I. Any suitable form of head counterbalancing means may be employed, and usually this takes the form of a long coil spring 14 having its inner end attached at I 5 to the press frame, and its outer movable end operatively connected at II to the head arm. With the motor means 8 idle or lie-energized, the tensioned spring means ll maintains the head in wide open position.

An air inlet and exhaust tube l8 communicates with the inner or closed end of the cylinder, and this usually is an air hose which flexes with the up and down movement of the cylinder. A control member, such as valve means it, is connected with the combination air inlet and exhaust tube It. Operation of the valve it, that is, the 0pening and closing thereof, serves to admit and exhaust air to and from the cylinder 8 for the purpose of closing and opening the pressing jaws 8 and 8.

The electrically controlled valve In the event an electric motor is used to drive the press, an electrical power switch will of course be employed in place of the fluid-power valve means It. The electrically controlled type of valve shown, that is, a solenoid actuated valve i, has a valve stem 20 which carries a solenoid core or armature 2! adapted to be actuated by a solenoid winding 22. A spring 23 tends to normally raise the valve stem when the solenoid is de-energized. and the energization of the solenoid returns it against the tension of. the spring to its lowermost position. Thus the valve I9 is controlled by energizing and deenergizing the solenoid 22. This is a poppet type valve and it is found to be satisfactory for use in this new combination when a pneumatic motor means is used to operate the press. The valve i8 and its operating solenoid 22 may be mounted on the frame I or on the cylinder 9. or otherwise conveniently mounted; the present illustration being purely diagrammatic.

An air-pressure supply conduit 24 connects with the valve housing I! to feed air under pres- -(the lower end) of the valve chamber 28. for the 'motor 9 is stalled against further movement by I other end (the upper end) of the valve chamber 26, thus shutting ofl an exhaust port 2| when the inlet valve 2"! is open. Thus the compressed air is conducted from the air-supply conduit 24 to the hose i8 and motor 8. The inlet valve 28 and exhaust valve 21 are fixed on the valve stem 20 and work in unison. Thus one valve head is always closed and the other is open. so that-when the inlet valve 2! is open, the exhaust valve 21 V is closed and the press is closing or And conversely. when the inlet valve 2! is seated as in Figure 1, the exhaust valve 21 is open to ex haust the motor cylinder 1 thmugh the exhaust port 20 to atmosphere, and the press is then open or in the act of opening.

The foregoing features of constructions-re presented as an exemplary form of power-actuated textile press for laundry or other work, for the purpose of now explaining the control instrumentality combined therewith and constituting our new combination. It will be noted that the fast closing heated ironing head of a laundry-ironing press presents a hazard to the safety of an operator because he or she is continually engaged with her hands and arms in the danger zone near or within the path of the head.

The capacity responsive circuit of Figure 1 as its use to control the pres:

For controlling the operation of the press and I safeguarding the operator working near the danger zone, that is, within the path of the ironing head 5, we may use the capacity responsive circuit of Figure 1 showing one form of the invention.

This circuit comprises an oscillator tube 82 and i an amplifier or power tube 38 arranged to operate directly on alternating current from the power line or main 84. A switch It connects the capacity circuit'to the power main ll. a wire 88 which forms a part of the circuit, being connected to one terminal of the switch I! and a wire 21 beingconnected to the other terminal thereof. The tubes 82 and 83 are ofthe independently heated cathode type having heater filaments 4s and I, respectively, which-are connected in series. The filament I has one end connected to the wire 38. while the filament 4! has one and connected through a resistance #2 to the wire 31. A wire 42 connects the other ends of the filaments 40 and CI in series.

The oscillating tube 82 should preferably be a shar cut-off tube and has a cathode ill, a control electrode or control grid ll, a screen grid 4!. a suppressor'grid 41, and a plate 48 usually called an anode.- The control grid 45 is connected through a variable condenser to one end of an oscillator coil It, the other end of which is connected to the wire 8E. The cathode M is connected at a point 53 to the coil 80 and also through a grid leak resistance 54 to the control grid 48. The screen grid 48 is connected through a radio frequency choke 53 to the wire 31 to give it asuitable operating potential, while a condenser 58 connects this screen grid 48 to the cathode 44. The anode 48 is connected directly to the wire 31 from which it receives its operating potential.

The tube 33 has a cathode 14, a control grid 18, a screen grid 18, and an anode or plate 11. The cathode I4 is connected to the end of the filament 4| at the wire 43, so that it is separated from the wire 38 by the resistance of the filament. The control grid 15 is connected through a grid leak resistance 18 to the wire 38. The control grid 15 is also connected through the condenser 18 to the cathode 44 of the tube 32. This condenser has low impedance to the oscillating frequency of the capacity circuit. With the arrangement shown, whenever the tube 32 is oscillating, an oscillating potential occurs across the resistance I8 and is therefore applied between the control grid I and the cathode 14 of the tube 33.

The anode ll of the tube 33 is connected through the coil of a relay 82 to the wire 31, a condenser 83 being shunted across this coil. The condenser 83 stores and smooths the half cycle pulses which come through the tube when anode current is flowing to produce, in effect, direct current in the coil of the relay 82. This relay has an armature 84 attached to a spring contact 85 which is adapted to make electrical connection with a contact 88 attached to the wire 31, when the relay is energized. When the relay 82 is deenergized, the resiliency of the spring arm separates the contacts 85 and 88. The contact 85 is connected by a wire 81 to the solenoid 22, the other end of the solenoid being connected by a wire 48 to the wire 38.

The control grid 18 of the tube 33 is normally held negative with respect to the cathode 14 so that the current to the anode ll of the tube 33 through the relay 82 is insufllclent to operate the relay. When the tube 32 is oscillating, however,

the positive half-cycles of the oscillating potential across the resistance 18 swing or cause the potential of the control grid 15 to become suiilciently positive to increase the anode current" denser 8| should be made large enough so that it will offer little impedance to the oscillating current, but its impedance to the 8D cycle alternating current of the power main should be high. This condenser is used so that in the event or when one wire of the power main 34 is grounded, that grounded wire may be connected to either the wire 38 or the wire 3'! of the capacity circuit without-afiecting the operation thereof, in a manner known to the art.

The chassis or box 52, housing the capacity circuit parts, is. mounted on the frame 1 of the press in some convenient location, as shown for example in Figures 6 and 7. It will be understood that th casing 52 is grounded by virtue of its attachment to the press frame l and thus that the lower end of coil 58 is effectively grounded for the oscillating frequency by condenser El.

Hereinafter, the chassis box or casing 52 (Figures 1, 6 and 7) will be used to designate the capacity responsive circuit as a unit or element in this new combination.

With the arrangement just described, the tube 32 may be made to oscillate by properly selecting the point 53 on the oscillator coil 50 and adjusting the variable condenser 48 to a suitable value. As long as the potential between the grid and the nd s greater by a certain amount than the potential between the cathode 44 and ground, sustained oscillations of the tube 32 will be produced at a frequency depending upon the inductance value of the coil and the capacity of the condenser 48 together with certain other circuit capacities. If the capacity of the control grid 45 to ground is increased suilicientiy to decrease the potential of the grid below a certain amount, the tube 32 will stop oscillating. Thus, the tube 32 and its associated parts represent, in effect, a circuit with two conditions of operation. In one condition, the tube 32 is oscillating; in the other condition it is not oscillating.

The components of the capacity responsive circuit, or control unit 52, may be subject to considerable variation. However, excellent results have been obtained by using a number 6J7 tube for the oscillating tube 32 with the oscillator coil 50 composed of 100 turns of #26 copper wire wound on a 1 /4 inch mandrel for suitable inductance in this circuit. The remaining component values were as follows:

Condenser 4925 to 200 micromicrofarads Grid resistance 54l0 megohms Radio frequency choke 55-6 millihenrys with 200 ohms resistance Bypass condenser 56-mica, .001 microfarad Coil of relay 82-1000 ohms resistance Condenser 836 microfarads Grid resistor 'I82 megohms Condenser l8.l microfarad This circuit oscillated at a frequency in the neighborhood of 300 kilocycles.

, The change in the condition of the foregoing oscillating circuit is used to control the operation of the press, and such change is caused by the relative position of any part of an operator's body, or her arms, with respect to electrodes 52 and 63. These electrodes are carried respectively by the head 5 and the table 2 of the press I, and are connected to the grid 45 of the tube 32 by means of a wire 88 through a condenser 6|. This condenser Bl should have low impedance at the oscillating frequency, but high impedance to the 6D cycle current, and it serves to protect tube 32 in case the electrodes '62 or 83 are grounded and the wir 3'! is connected to the grounded side of the power main 34.

The electrodes 82 and '83 are connected together by a wire 18, and they possess a capacity to ground symbolized by the condenser 64, shown in dotted lines. If a potential difference is caused to exist between the electrode means 82, 63 and ground as,for example, by the application of an oscillating voltage, there is produced an electric field which is composed of electrostatic lines of force extending from said electrode means to all adjacent conductors having a potential differing therefrom. The greatest concentration of these lines of force will be between the electrode means 62, 63 and the metallic mass of the press as a whole, including the head and buck. Note also that the electrostatic lines of force will also exs,ses,7ao

tend outwardly into space, as best we understand the electrical phenomenon at this time.

If, a person moves into the vicinity of either of these electrodes 02 and 03, and thus into the electric field, the lines of force tend to concentrate in the body of the person, and thus the capacity of the condenser 64 is increased by the capacitanceIoi the electrodes to the body of the person. The condenser 49, is adjusted so that this ing material and are appropriately shaped to provide a clear working space adjacent the pressing laws and to create an electrostatic field oi maximum responsiveness. The electrodes are placed along the front and at least portions of the sides of the head and buck. Mounted as shown (Figure l), the lower electrode 08 afiords suflicient room between itself and the buck I so the damp laundered work being ironed can be tucked in around the base of the buck and rest on the table without coming into contact with the electrode. A metallic member, say'bar material, or copper or brass tubing, about inch in diameter or thereabouts, is satisfactory as electrode material,

Both electrodes 62 and 00 are necessarily insulated from any metal parts in their vicinity and also are spaced from such parts, so as to reduce to a minimum the capacity between the electrodes and the metal parts of the press frame. Any type of stand-of! insulators may be used for so spacing the electrodes, as, for instance, posts 00, one of which is shown in detail in Figure 3. These posts may be made of micarta-," "bakelite," hard rubber, fibre, or any other substance having good insulating characteristics and suificient strength to support the electrodes. The posts 00 may be supported by means or a threaded stud 00 screwed into a tapped hole 61 and has its outer end screwed into a tapped hole 88 in the post. The electrode is secured to the outer end oi each post 60 by a screw 60 through the tubular electrode and set in a tapped hole I2 in the outer end or the post.

The compensating condenser of Figures 1, and 5 When the head 5 and buck 0 are separated (press open), the combined capacity to ground of the electrodes 02, 63 is greater than when the press is closed. In order that the machine may be sate against closing on the hand or the operator when the press is open or in the act of closing, the capacitance of the combined electrodes 02, 03 to ground is increased or at least mainthe press and moves toward the electrode 03 durthrough holes in the strip and the lock nuts IOI log the closing of thepjress, until the predetermined or safety-first" position is reached, and then to decrease the capacity to ground. The condenser is shown in detail in Figures 4 and 5. The reason for the decrease is to confine the field between the electrodes 62, 63 to a minimum spread or area so that the press will not be sensitive to unintentional opening from closed position unless the operator is in the position she would occupy to handle work in the press. The condenser (Figures 1, 4 and 5) is made adjustable, so that the configuration of the capacitance curve may be changed to fit the requirements of different presses.

This condenser 00- may comprise a plate 9i of insulating material, such as "bakelite, mounted by screws 93 on abracket 92 attached to the press frame I by any suitable means. At the wide end of the insulating plate 0| we provide a plurality oi screws 00 having enlarged flat condenser heads or plates I00, these screws being arranged close together in an arc, the center of curvature of which is the axis of a shait 04 at the narrow end or the plate BI. The screws 80 are threaded into tapped holes in the plate 0| and may be provided with lock'nuts IOI to secure them in the insulating plate. The screws may also have slot-. ted ends I02 to permit adjustment with a screw driver.

The shaft 04 may be rotatably mounted in a hub or tube 05 forming a part of the insulating plate 0|. An operating arm I00 is fixed by screw 91 to one end of the shaft 04, and a condenser arm I03 is fixed to the other end of the shaft 94 by a screw 98. The condenser arm I03 extends a distance sufficient to terminate it adjacent the arc of the hat condenser heads I00. This condenser is provided with an enlarged movable condenser plate or head I04 which may be about the same size as the'stationary flat condenser heads I00. The arm I00 is spacedirom the insulating plate Si by the hub 06 sufllciently to permit adjustment or the screws 00 to position the series of fiat heads I00 at diflerent distances from the movable head I04. 1

side 01' the insulating plate 0| from the condenser arm I03 and at the point where the screws 00 pass through it, the screws passing also being tightened against this strip. This connects all of the screws 89 electrically together and the wire I08 connects the strip I05 to the electrodes 62 and 03. The shaft 84 is grounded by a suitable connection or wire I01.

The condenser arm I03 is operatively connectedito the head arm 8 of thepress (Figure 1) soas to move as the arm 6 moves. For this purpose the lever I08 is attached to the shaft 34 in any desirable manner and may extend radially from the shalt to be pivotally connected at I09 to-the 'lower end of a link H0. The upper end or this link may be pivotally connected at III to another lever II! integral with the head arm 8 adjacent the frame pivot I; When the arm 0 swings to lower the head, the link III is raised, thus moving the lever I00 and rotating the shaft 04 to swing the arm I03. The entire condenser unit 00 may be enclosed in a suitable housing II! shown in Figure l.

As shown, the movable condenser plate or head I04 of arm I03 is at the left-hand side of the device when the press is in open position. The effective capacity to ground of the electrodes 02 and 00 in this position will be the actual capacity to ground, plus the capacity between the head I and the head I or the left-hand screw is of the variablecondenser ll. As the press closes and the arm rotates in a clockwise direction, the heads I" of the screws 9! become successive closer to the head I", so that the capacity between these heads I" and the head I increases the capacity to ground as the press head moves from wide open position toward closed position to a safety-first position.

In adjusting this type condenser for a particular press, a curve may first be taken by a capacitance bridge of the change in capacity to round or the electrodes 82 and II {or movement of the ironing head from open to closed position and without the condenser connected in the circuit. Then the condenser ll may be independently adjusted to provide a predetermined compensating capacity curve for the machine in which the condenser is to be installed.

The actual range of the compensating condenser 8| will depend largely on the particular type of press to which the invention is applied, but it will probably be in the neighborhood of 5 micromicrofarads. The minimum value 01' the condenser should be as low as possible.

Sensitivity decreased when press closed While using the press it is desirable to have the control extremely sensitive when the laws of the press are separated so that it will be absolutely impossible for the operator's hand to be caught by the head as it descends towards the buck. However, after the head has reached the buck there is no danger to the operator and hence the head may be allowed to remain in position until the garment is completely pressed. It is desirable, therefore, that the sensitivity or the control be decreased when the press is closed so that the casual approach oi the operator will'4o not open it.

The foregoing decrease'in sensitivity is readily accomplished by turning the screw II at the righthand end of the line oi screws of the condenser 80, so that its head ill will be as far as possible away from the head I" on the movable arm ill. The capacity when the arm is in this press-closed position will be a minimum. As this position or the arm corresponds to the closed position of the press, the capacity will be decreased sufficiently at such position as to cause the bridge or field between the electrodes to be confined or drawn in from a wide area and confined to a small area around the edge of the head or buck and thereby to render the control less sensitive. The adjustment or this last screw 8! or the condenser can be made such that the operator can move about in front of the press without the press opening, but as soon as she approaches beyond a predetermined distance (depending on the adjustment of the right hand condenser screw), the press will open, and of course the press will open at any time'that she touches either or both of the electrodes 82 and II.

Great care should be taken in assembling the parts of the oscillator circuit, especially those portions 0! the circuit which carry the high irequency current. When the parts are properly assembled, no substantial eilect will be produced by changes in humidity or temperature 0! the room in which the press is used. Where proper precautions are not taken to prevent the effect of humidity and temperature on the oscillating circuit and other parts or the circuit associated therewith, we may prefer to leave the circuit on continuously. or at least to turn it on for a suitable period of time beiore operation oi. the press, to insure that all the parts of the circuit will be uniformly heated and at their proper operating temperatures before the press is used, Note also that the leads or wires connecting the various electrodes to the circuit should be as short as possible, well insulated, and rigidly suppcrted. Any unnecessary movement of the wiring may result in changes in the sensitivity of the circuit.

Operation of the press 0/ Figure 1 In the operation of the press, assuming that the operator has made the proper lay of a garment on the buck, she withdraws her hands or turns away from the press. As she moves a predetermined distance away from the press, the combined capacity to ground or the electrodes 62 and I3 (capacity of condenser 64) is reduced because she is moving out of the electrostatic field. This reduction of capacity to ground of the elec trodes 82 and 63 raises the potential oi the control grid 4' of the oscillating tube 32 with the result that this tube breaks into oscillation. Oscillatlon oi the tube 12 produces an oscillating potential across the resistance 18 which swings the control grid 15 of the tube 33 in a positive direction with respect to the cathode H of that tube, thus increasing the anode or plate current through the tube and through the relay 82 sufiiciently to operate the relay.

Energization oi the relay 82 draws the armature l4 towards it, thus making or closing the contacts I! and I, thereby sending current from the wire I! through said contacts, thence through wire 81, through the solenoid 22 and wire 88, and back to the wire ll connected to the other side of the line I4. This energizes the solenoid 22 and draws the valve rod 20 downwardly against the tension of the spring 23, opening the inlet valve 25 and closing the exhaust valve 21, thus admitting air under pressure to the flexible conduit II which delivers it to the cylinder 8 and forces the piston ll upwardly to swing the arm a and close the press.

At this point the operator is out of the electrostatic field and may be attending to other duties connected with her work, such as making a lay of a garment on another press in the nearby vicinity.

After the press has been closed for a sufilcient period 01' time to completely iron and dry the garment and the operator has completed her other duties, she again approaches the press. When she moves near enough to sufilciently aflect the electrostatic field, the combined capacity to ground of the electrodes 62 and 63 (capacity oi condenser I4) will be thus increased, which will reduce the potential on the control grid All of the tube 32 to the point where this tube will stop oscillating. Removal of the oscillating potential from across the resistance 18 will lower the potential of the control grid 15 of the tube 33 with respect to the cathode 14 or that tube, which will reduce the anode or plate current of the tube a to such an extent that the relay 32 will release its armature l4 and break the contacts I! and ll. This breaks the circuit through the solenoid 12, thus deenergizing the solenoid and permitting the valve stem 20 to rise under the influence oi the spring 23. This closes the inlet valve I5, 28 and opens the outlet valve 21, 2!, which allows the air to leave the cylinde a, and allows the arm l of the press to swing in a GOill1- tar-clockwise direction under the tension oi the the buck.

2,sss,7so

spring II. The press is now open for the operator to remove the finished work and insert another article to be press-ironed.

If the operator should start to leave the press and then suddenly turn back to it as the head I is descending, the change in capacity to ground of the combined electrodes 62 and 63 will cause the head to open again, and therefore under this arrangement it is absolutely impossible for the operator to catch her hand or any other part of her body in the closing press, because it will always open whenever a part of her body comes in proximity to either the head or buck. However, by virtue of the adjustment in the variable or compensating condenser, the circuit is less sensitive when the head is completely closed and so she may approach the press closer without having it open than would be true during the danger period when the head is closing. As

explained, this operating sensitivity may be adjusted as desired.

The positioning of the electrodes .52 and II in the manner described, electrically insulated from adjacent metal parts, provides certain desirable features relating to the operation of the press. The large conductive mass of the head I acts as a shield for the electrode 62, absorbing or concentrating electrostatic lines of force in its direction with the result that the direction or area of the useful field is controlled and this portion of the field may be made extremely sensitive. We may prefer therefore, to mount the electrode I2 adjacent the lower edge of the head I, in which case the sensitive field will extend through a wide angle around the edge of the head, making the control of the press responsive to any sufllciently large object, possessing'suitable dielectric constant approaching this outer edge of the head within this area.

In like manner the metal table 2 of the press and the buck I act as shields for the electrode 80 to confine the sensitive electrostatic field to the space above and in frontvot the electrode 60. These two fields produced by the electrodes 62 and 83 thus cooperate to form substantially a single field between them which must be intercepted by any object interposed between the head and buck, and which extends a sufficient distance at the front and sides of the press to effect the operation thereof in the manner described,

as the operator moves towards and away from the press. v

The movable electrode of Figures 6 and 7, with a condenser as in Figures 8 and 9 In some instances we may prefer to use the arrangement illustrated in Figures 6 to 9 inclusive, with any suitable condenser. In this arrangement a movable capacity responsive electrode III is positioned in the space between the head and buck when the head is in'the raised position and is caused to swing out towards the front of the press when the head is broughtdown against The swingable electrode III may be mounted between two arms III which may be pivotally supported on the head I by means of pivots Ill. The arms III may be preferably made of insulating material, such as Bakelite. "micarta, or any other insulating material which will have suiilcient strength to support the electrode and insulate it from the head. Two arms I I may be used, positioned one at each end of the head, and it will be understood that the arm at the far end of the head in the views shown in Figures 6 and 7 will be a duplicate of the arm shown. The electrode IJI may be a bar, or preferably a tube, of brass or copper or other suitable conducting material, having a length suillcient to I brought down, the movement about the two centers will swing the electrode III outwardly to the position shown in Figure 7. 'Ihe link III may be bent horizontally so as to make the proper pivotal connection between the arm III and the shaft I20, as these two pivot points may not be in the same plane.

We may use the link III as an electric conductor for the electrode I I0 and for this purpose may connect it by means of a wire I2I to the electrode. However, the other end of the link I II must be insulated from the frame I, and we may therefore separate the link Ill into two parts by means of an insulating member I22, the separation being at a point adjacent the shaft I20, so that the longer portion of the link III may also act as an electrode for the purpose of the invention.

, The capacity control chassis I2 may be mounted in any convenient location, such as indicated in Figures 6 and 7, below the shaft I20, and the link II8 may be electrically connected by means of a wire I28 to the capacity control unit. This wire I23 corresponds to the wire 00 of Figure 1.

The shaft I20 may be rotatably mounted in a bearing I24 carried by a box I2I secured to the press frame. Thi box houses a condenser and is shown above the capacity control unit I2. The shaft I20 extends inside the box and has attached thereto a gear sector I20 which meshes with a gear I21 fixed on the shaft I20 of a variable condenser I20 (Figure 8) in the box I". This condenser may be mounted on an insulating plate I30; and it may be similar to-the condenser II, shown in Figures 1, 4 and 5. But it is shown here as comprising a single movable plate Ill, mounted on the shaft I20, and a cooperating pair ofplates I02 fixed with respect to the insulating plate I30. The two or more stationary condenser plates I32 are electrically connected in any well known manner, and they are shown to be electrically connected by means of a wire I to the wire I23 which in turn connects the electrode link ground on the metal box I 20 by the wire I.

In some instances, we may Provide additional electrodes I31 and I30 mounted respectively at the front edge of the head I and at the front of the frame beneath the work table 2. The electrode I31 may be a conductive bar or tube and supported by means of insulating posts III on the front of the head. This electrode III may be a little shorter than the head I and is electrically connected to the electrode link III by a wire I40. The electrode III below the table 2 may be similarly supported by'means of insulatin posts III at the front of the press. This electrod I is electrically connected by means of a wire I42 to the wire I20 leading to the capacity control unit I2.

All of the electrodes I II, III and III, and including the link III, which acts as an electrode, are connected to the capacity control unit, as is also the variable condenser Ill, I28. When the operator approaches any of these electrodes, therefore, the capacity responsive circuit (housed in chassis box II!) will respond and open the press in the manner described in connection with Figure 1. The electrode III, swinging into the space between the head and buck, insures the sensitivity of the control to the presence of an object of a predetermined nature in this space. The additional electrode I38 may be desired to prevent the tendency of the press to close before the operator has completely finished the lay of the work in case she has removed her hands momentarily from the buck.

The variable condenser I29 is used for the same purpose as the condenser 80 of Figure i. We have found such a variable condenser particularly desirable where the swinging electrode is used, as movement of the electrode out from the space between the head i and buck l alters its distance from the head and hence change the capacity to ground Accordingly, the condenser palte Ill should be specially shaped to provide the necessary changes in capacity as the press opens and closes.

In Figure 9, the condenser plate III is shown in its position of minimum capacity where it would be when the press is open. The ratio between the gear 111 and the gear sector IN is such that the condenser plate will rotate through at least 180 when the head moves through the necessary angle to open and close the press. As in the compensating condenser SI of Figure 5, the capacity to ground of condenser I25, I28 (Figures 6-9) may be decreased when the press is closed by arranging the rotation of the condenser plate III so that it begins to pass out of the space between the fixed condenser plates I32 when the ironing head 5 has approached so close to the buck I that an operator could no longer get her hand therebetween.

Grouped operation of presses Fimu'e This invention lends itself particularly to a laundry plant layout where one or more operators attends to several presses. A three-press ironing unit, each press having capacity control, is diagrammed in Figure 10 where presses I", I and I41 are arranged in a group, say for one operator. Dresses are indicated respectively by the dotted lines Ill, I49 and I", and the operator may go from press to press as indicated by the arrow. As soon as the lay on the first press I" has been completed, she leaves that press without having to think about closing it or to make any extra control movements with her hands or feet, as in conventional presses.

The operator can thus step to the next press I" which will open at her approach. She then makes the lay on that press and moves on to next press l-l'l. As she moves, press I will close and press I will open. By that time the work on the first press I may be dried and pressure-ironed, and she will and this first press open by the time her hands have reached out to remove or change the position of the work. Several presses may be thus operated at a minimum of time and eifort, with the result that the openato: can turn out more work with much less fatigue and without attention to manual controls as in conventional practice.

The electrostatic fields of this group of.

The field lines I49, etc., are entirely diagrammatic and in some forms of the invention actually may exist in a more concentrated and closely confined form around the pressing jaws, according to the third form of electrode means next described.

The head and buck as capacit sensitive electrodes, Figures 11 to 13 In some instances, it may be desirable to insulate both pressing members or laws, the head and buck, from the press frame and use the head and the buck as the capacity sensitive electrodes. An example of this third form of electrode construction is shown in Figures l1, l2, and 13. This feature provides for an electrical control field more effectively concentrated at the danger zone, that is, at the front edges of the head and buck. This type of electrode means is well adapted for use in connection with a group of presses (Figure 10) attended by more than one operator, although the type of press construction may make it Just as applicable and eilective for single operator use.

In Figure 11, a typical laundry or textile press, similar to that shown In Figure l, and having a frame III, is provided with a buck I52, and a head I53 which is mounted upon the head arm I for cooperative motion with the buck. The power mechanism may be exactly the same as already described in connection with the previous figures and corresponding parts have been given the same reference characters.

The head I53 may be insulated from the arm I by means of the insulated ball and socket attachment shown in detail in Figure 12. The upper end of the arm I may be provided with a pair of enlarged portions I55 having openings I56 extending through them: at substantially right angles to the arm. Inasmuch as both of these enlarged portions and their associated attachments are exactly the same, only one has been shown in the drawing. A rod I51 may be positioned in the opening I56 to extend through this opening below the lower edge 0! the arm I. The rod may be secured in this position by suitable nuts I58 and IE8 at the top and bottom thereof, these nuts being threaded on the rod. Insulating washers I60 and IBI may be provided at the top and bottom to space the rod in the opening I55 without touching the walls thereof, metallic washers I82 and I" being provided under the nuts I58 and ISO respectively to insure greater strength.

The lower end of the rod I51 may extend downwardly a short distance from the arm I" and may terminate in a ball IN. The head I" of the press may be provided with a pair or raised portions I to cooperate with the balls I on the lower ends 01 the two rods I51. Each of" these raised portions may have a spherical recess I", slightly larger in diameter than the ball. I, and the ball may fit into this recess with an insulating shell I81 between the two metal shell 161 may be made of Bakelite, .id'icarta, (3:116 like, and may be molded around. the ball A pair of clamping members I Bl are provided to secure the head to the balls. To this end each of the clamping members may he provided with a spherical recess ISO, to fit on the upper side oi the ball I64 and shell I61, and a hole 1'10 to accommodate the rod I51. Each clamping mem her I" may be provided with a pair of openings III, spaced from the central recess ill, to receive stud bolts I12 which may be threaded into suitable tapped holes I13 provided in each of the enlarged portions I85. of the head I53. The holes I1I are made larger in diameter than the stud bolts I12, and insulating washers I14 may be used under the heads of the bolts in order to prevent the bolts from touching the clamping members I88. By tightening the bolts I12 the clamping members I88 ma be held rigidly with the balls I84 between them and the head. I

The insulating shells I81 and the washers I14 prevent metallic contact between the balls I84 and the head. .In addition the rods I51 are insulated from the arm I54 by means of the washers I88 and IN already described. This provides a rigid adjustable support for the head I53 permitting movement of the head about the balls I84 to align it with the contour of the buck. At the same time the head is .completely insulated from the frame, the double insulation reducing the capacity through the connecting-means.

It is usually desired to heat the head I53 by means of steam, and when this is done-the head may be made hollow and steam may be passed through it. In order to maintain the insulation of the head in spite of the steam connections we may provide insulating fittings I15 which may be the same for both the inlet and outlet pipes. In Figure 11 the steam inlet connection is shown as comprising a pipe I18 which is threaded into a suitable fitting I11 which may be rigidly'supported on the frame II of the machine, as by means of a bracket I18. A flexible tube I18 may be attached to the fittings I11 and may connect with the head I53 through the insulating connection I which is shown in detail in Figure 13. This insulating connection may comprise a cylinder I88 of insulating material such as Bakelite," provided with two metal discs I8I, at either end, for making pipe connections thereto. Each ofthese discs may have a threaded tubular extension I82 at the center thereof, for connection to pipe fittings, with a hole I83 extending through the disc and extension for the transmission of steam. Suitable holes I84 are provided around the periphery of each of the discs I8I to receive stud bolts I85 which may be threaded into tapped holes I88 in the insulating cylinder to secure the discs I8I at either end of the cylinder.

The insulating cylinder I88 may have an opening I81 through its center which may have an enlarged shallow portion I88 at one end and a deeper-enlarged portion I88 at the other end. A glass tube I88 may be mounted in the opening I81 through the center of the cylinder and may have a flange I8I at one end thereof, adapted to fit into the enlarged portion I88 of the opening through the cylinder. The other end of the glass tube may extend a short distance into the enlarged portion I88 of the opening, but the tube is preferably shorter in length than the insulating cylinder so as not to contact with more than one of the metal discs.

The left end of the connection, as shown in Figure 13, is screwed into a suitable tapped opening therefor inv the hollow steam-heated ironing head I53, while the flexible steam inlet pipe I19 is connected to the other end of the insulator I18 by means of a fitting I82. Steam thus enters the movable head I53 through the flexible insulating connection I15 in the direction of the arrows, and is prevented from directly striking the insulating material by the lass tube I98, which therefore protects it from the effect of the live steam. Steam leaves the ironing head through another adjacent the frame pivot 1.

flexible tube and insulating connection of the same type as just described and it is attached at the opposite end of the head, the two connections being arranged so that the steam circulates through the head for heating same.

The insulating means I81 and I15, etc., operatively mounts the steam heated ironing head I53 on the press frame I5I, and thus the head may be used as a capacity sensitive electrode. Steam may also be circulated through the stationary buck I52 for heating it, and the insulating connection I15 with an ordinary pipe connection may be used for that purpose; and thus the buck also may be used as a capacity sensitive electrode.

The buck I52 is insulated from the frame I5I by providing openings I93 in the top of the frame (Figure 11) through which bolts I84 extend without touching, the nuts I85 on the bolts being protected from the underside of the frame .by insulating washers I88. The buck itself may rest upon the table I81 which is preferably metal and, in this case, separated from the frame by a heavy insulating sheet I81. Thus, the buck and table I81 are connected together, but they are completely insulated from the frame I5I.

The head I53 and buck I52 of the press, to-

gether with the metal table I81, function as the The compensatingv condenser of Figures 11, 14 and 15 In the use of the insulated head I53 and buck I52 with metal table I81, it is desirable also to provide a compensating condenser, the capacity of which will change as the head moves with respect to the buck, for the reason heretofore described in connection with previous forms of the invention. This condenser may take the form of either of the two heretofore described (Figures 4, 5, and 8. 9) or the third form now described and shown in Figures 11, 14 and 15.

In this third form of condenser, its movable element comprises a tube 288 of thin metal rotatably mounted inside of an insulating tube 28I which, in turn, is secured between spaced mounting brackets 282 attached to the press frame I5I, as by screws 283. As shown, the two spaced brackets 282 are provided with holes in which the insulating tube 285 is tightly fitted and held stationary.

The metal tube 288 is oscillated within the insulating tube 28I by a lever 284 which is attached to one end of the tube 288, as by soldering or welding, noted at 285. A link 288 has one end pivotally connected with the outer end of the lever 284 and its other end pivotally connected with a lever 281 (Figure 11) on the head arm I54 When the arm I54 rotates in a counter-clockwise direction to close the press, the lever 281 also rotates and raises the link 288 which oscillates the condenser tube 288 within the insulating tube 28I.

The metal tube 288 may be cut out at its center at 288, such cut-out portion shown in this instance as extending substantially two-thirds around the circumference of the tube. A metal plate 209 is positioned on the outside of the insulating tube 20| and may be bent to conform to the contour thereof and fastened thereto by means of a screw 2 0.

When the condenser is in the position shown in Figures 14 and 15, the cut-out portion of its metal tube 200 is adjacent the outer plate 203, but when the lever 234 is moved upwardly to turn the tube 200 in a clockwise direction, as viewed in Figure 15, the solid portion of the tube indicated at 2 (Figure moves into the vicinity of the plate 209 thus increasing the capacity between the tube 200 and the plate 200. The tube 200 may be connected to ground or the press frame by a wire -2|2 held by a screw 2|3. The plate 209 maybe connected to the wire I33, leading from the head and buck, by means of a wire 2|4 secured by the screw 2|3.

As already explained, when the head of the press moves towards the buck the combined capacity to ground may not change proportionally, and hence it may be desirable to cut the tube 203 or the plate 209, or both, in an uneven manner to compensate for this unequal change in the capacity as the head moves. Inumuch as this non-proportional capacity change would be different for difierent presses, especially those of diflerent size and shape, we may prefer to use the type of condenser illustrated in Figures 1, 4 and 5 so that the condenser may be quickly adjusted for the particular press with which it is used. The operation of the press of Figure 11 is generally similar to that already described in connection with Figure 1.

The circuit of Figure 16 First, it will be explained that the circuit shown in Figure 1 operates on raw alternating current. In other words, alternating voltages are applied to the plates of the tubes 32 and 33. The control relay "operates on the positive half of the alternating current cycle, the bridging condenser .33 tending to hold the relay from one half wave to the next. The value of this condenser, necessary to eliminate relay chatter and insure adequate relay current, may be large enough to keep the relay 82 energized for several cycles after the tube 33 has ceased to pass current. There may he, therefore, in using the circuit of Figure 1, a delay in the response of the relay 32 corresponding to several cycles of the alternating current which, for 60 cycle alternating current, may be as great as one-tenth 0/10) of a secand.

Where the ironing head of a press is heavy and closes at high speed, a perceptible movement, in some instances several inches, may occur during the delay aforesaid, that is between the tim when the oscillator tube 32 stops, due to the presence of the operator's hand in the path or danger zone of the press head, and the time when the relay "responds. In order to avoid this time delay and greatly speed up the response or the relay to the presence of an object between the Jaws of the press, we prefer to use a faster circuit. 'I'hispreferred and faster control circuit, and a Dress controlled thereby, is shown diagrammatically in Figure 16. This second form of circuit can also be used in connection with forms of the invention previously described.

This faster operating circuit comprises an oscillator tube 2||, an output tube 2", and a buffer amplifier tube 2|! connected between these two tubes. All of these tubes may be of the heater type, and while the heaters of the tubes may be operated on alternating current, it is preferable to provide direct current for the other elements of the tubes.

To this end, we may 'use a transformer 220 having a primary winding 22| which may be connected directly to the alternating current power mains 222. The transformer 220 may also have a filament supply secondary winding 223 which may be directly connected across the filaments or heaters 224, 225, and 225 of the tubes 2|1, 2|8 and 2| 9 respectively. The wiring for these filaments has been omitted for clarity. A high voltage secondary winding 22! on the transformer 220 may be connected between the anodes 228 and 229 of a full wave rectifier tube 235, the filament 23| of which may be independently energized by a separate secondary winding 232 on the transformer 220. The mid-point of the secondary winding 22! may be connected to a wire 233 and to ground at 234, while the filament 23| of the rectifier tube 230 may be connected to a suitable filter network, including the choke 235 and condensers 236 and 231 which are connected between opposite ends of the choke 235 and the grounded wire 233. A wire 233 may be connected to the opposite end of the choke 235 and forms the high voltage supply wire for the circuit.

The oscillator tube 2|| may have a cathode 243 which is heated by the filament 224, a control grid or control electrode I, a screen grid 242, a. suppressor grid 243, and an anode 244. The suppressor grid 243, may be connected to the cathode 240 inside of the tube. The anode 244 may be given a positive potential by connecting it directly by means of a wire 245 to the positive supply wire 238, and the screen grid 242 may also be given a positive potential from the wire 245 through a radio frequency choke 246. The screen grid 242 may also be connected through a condenser 24'! to the cathode 240.

The control grid 24| of the tube 2|l may be connected through a variable condenser 253 to one end of a coil 25l, the other end of which may be grounded at 252. The cathode 240 may be connected to a point 253 on the coil HI, and a grid leak resistance 254 may be connected between the control grid 24| and the cathode 240.

With the circuit connected to the tube 2|I, as Just described, the tube acts in the same manner as the tube 32 of Figure 1 with the exception that the plate supply is constant.

Also similarly to the tube 32 of Figure 1, it is the change in the circuit from the oscillating condition to the nonoscillating condition that is used to operate the control means. To this end we provide the buffer amplifier tube 2|3 which may have a cathode 258 heated by the filament 225, a control grid 25!, a screen grid 23!, a suppressor grid 2", and an anode 232 The suppressor grid I may be connected inside the tube to the cathode 253, as shown, and the screen grid 260 may be given a positive potential from the wire :45 to which it is directly connected. The control grid 253 may be connected directly to a point 253 on the coil 25| which is near the grounded end of that coil. The cathode 253 may be connected to ground through a biasing resistor 234 which may be shunted by a condenser 245.

The anode circuit of the tube 2|! may comprise a tuned tank circuit 265 including the coil 26! and the variable condenser 233, one side of this circuit being connected to the anode 232 and theother side to the wire 245, whereby the anode receives a positive potential. The tank circuit 266 is tuned to the oscillator frequency.

212, a suppressor grid 213, suppressor grid 213 may be connected to the cathode 2 inside the tube.

end to make the cathode 2 more positive than the grid and thus maintain the grid negatively biased, 21! to a point 218 on The anode 214 of the tube through the coil of current through the tube 2 I 8.

In one instance where this circuit was used with good results, the oscillating tube 2|! and as given in connection with 1. Some of the other more important values were as follows: a

Bias resistance 284'between 3000 and 5000 ohms Bypass condenser 285-Jmicrofarad Coupling condenser 269 .1 microfarad Radio frequency choke 211-between 6 and 8 millihenrys Coil o1 relay Z52-6500 ohms resistance Relay condenser 283-.05 mlcrofarad Operation of the circuit of Figure 16 In the operation of the circuit,

11 The oscillating voltage in the tank circuit 269 to the spect to the cathode 2H ticular connections used, such that the tube 2|8 will pass anode press and maintain it closed.

When a body oi a instance, the hand alternating Also by the use 01' the buffer amplifier we can connecting the load circuit across just a few turns 01' the coil "I at the point 268 which prevents losses-from the load from being reflected back into the oscillating circuit.

When the tube 2" starts or stops oscillating,

caused by the the head Ii 01' the press will be The response of the inertia oi the moving parts.

current were used and cycle impulses fed to the relay.

General discussion of advantages The circuits or both Figures 1 and 16 are so arranged that when a failure occursiin substantially able pressing jaws having an open any part thereof the relays 82 and 282 will be deenergized and will open the contacts 85 and 85 and 285 and 286. If the filaments of any of the tubes burn out, or any of the resistances, coils, or condensers in the circuit become shorted, or open circuited, the relays will be deenergized. In Figure 16 the fuse 290 in the anode circuit of the tube 218 will open the circuit through the relay 282 if a short circuit in the tube Us or in any other part of the circuit should cause the anode current of the tube M8 to increase beyond the normal current value.

It is understood that various modifications in the structure, as well as changes in mode of operation, assembly and manner of use, may and often do occur to those skilled in the art, especially after benefiting from the teachings oi. an invention. Hence, it will be understood that this disclosure is illustrative of preferred means of embodying the invention in useful form by explaining the construction, operation and advantages thereof.

What is claimed is:

1. A textile press comprising relatively movand a closed position, power operated means to cause said jaws to assume either position, a balanced electric circuit to control said power operated means, said power operated means acting in one direction to close the press for a predetermined condition of balance of said circuit and in the other direction to open the press for another predetermined condition of balance oi said circuit, a conducting member connected in said circuit and positioned to establish an electric field around the path of the operating movement of said pressing jaws, said conducting member having a capacity to ground which is alterable by the presence of a body in the vicinity of said conducting member, and means to decrease the capacity to ground during the final closing of the press.

2. A textile press comprising a pressing jaw a second jaw coasting therewith, the jaws having a relative movement, one toward and from the other, power means to effect such relative movement, means for controlling the operation of the power means including means to create an electric field comprising an electrode member irom which said field originates, and means to confine the electric field the path of movement of 3. A press comprising a pair or cooperating pressing members having relative opening and closing movement, power operated means in e!- the 'movable jaw.

iect such relative movement, a conductive member insulatedly mounted on one of said members, a second conductive member insulatedly mounted on the other of said members, and means to cause said power operated means to eiIect relative movement of said members when a body of a predetermined nature passes into or out of .the vicinity of said conductive members, the last means including a balanced electric control circuit operable from one condition of balance to another condition of balance by the presence of a body in the vicinity of the conducting members and being connected in circuit with said conducting members.

4. A press comprising a jaw member having a plurality of operating positions, power operated means to move said jaw member from one or said positions to another, a balanced electrical circuit having two conditions of balance, means to cause said power operated means to move said jaw member towards one of its operating posifor the most part around tions when said circuit is in one of its conditions of balance, means to cause said power operated means to move said jaw member towards another of its operating positions when said circuit is in its other condition of balance, an electrode insulatedly mounted on said jaw member, and means to cause said circuit to change from one condition of balance to the other when a body of a predetermined nature passes into or out of the vicinity of said electrode.

5. A press comprising a pair of cooperating pressing jaw members, power operated means to move said members into and out of engagement with each other, a balanced electrical control circuit having two conditions of balance, means controlled by the control circuit to cause said power operated means to move said jaw members when said circuit changes from one condition of balance to the other, an electrode insulatedly mounted on oneof said jaw members, a second electrode insulatedly mounted on the other oi said jaw members, said electrodes being connected in the control circuit, and means to cause said circuit to change from one condition of balance to the other when a body of a predetermined nature passes into or out of the vicinity of said electrodes.

6. A press comprising a pair of cooperating pressing jaw members, power operated means to move said members into and out of engagement with each other, a balanced electrical circuit having two conditions of balance, means to cause said power operated means to move said jaw members when said circuit changes from one condition of balance to the other, an electrode insulatedly mounted on one of said jaw members and in spaced relation thereto, a second electrode insulatedly mounted on the other of said jaw members and in spaced relation thereto, and means to cause said circuit to change from one condition of balance to the other when a body of a predetermined nature passes into or out oi the vicinity of said electrodes.

'1. A textile press comprising a head and a buck mounted for relative movement towards and away from each other, ower operated means to effect relative movement of said head and buck, a conductive rod shaped to conform to the contour of a portion of said head including the front and ends thereof, means to insulatedly mount said rod on said head in spaced relation thereto, and means to cause said power operated means to move said head and buck away from each other when a body of a predetermined nature passes into the vicinity of said rod and to move said head and buck towards each other when said body passes out of the vicinity of said rod, the last means including a balanced electrical. control circuit electrically connected to said rod, and being in one condition of balance when the press is open, and in another condition of balance when the press is closed, and changing from one condition of balance to the other by the presence of a body in the vicinity of said rod,

8. A textile press comprising a head mounted for relative movement tow away from each other, move said head and hue the head, insulating means to suppr adjacent the lower edge of said head and s i outwardly therefrom, a second eondi having substantially the same conii said first rod, means to insulatedly second rod in spaced relation to Still.

below the top surface thereof, and means to cause said power operated means to effect the separation of said head and buck when a body of a predetermined nature moves into the vicinity of either or both of said rods and to move said head and buck towards each other when said body moves out of the vicinity of said rods, the last means including a balanced electrical circuit electrically connected to said rod, and being in one condition of balance when the press is open, and in another condition of balance when the press is closed, and changing from one condition of balance to the other by the presence of a body in the vicinity of said rod.

9. A textile press comprising a head and a buck mounted for relative movement towards and away from each other, power operated means to move said head towards and away from said buck, a conductive rod shaped to conform to the contour of the lower outer edge of said head,

means to insulatedly position said rod in spaced relation to the lower edge of said head, a second conductive rod having a shape conforming to said first rod, means to insulatedly position said second rod in spaced relation to said buck and below the top surface thereof, means to electrically connect said rods together, a balanced electric circuit for controlling the operation of the power means, the control circuit being connected to said rods having two conditions of operation, the control circuit including means to cause said circuit to change from one of its operating conditions to another when a body of a predetermined nature passes into or out of the vicinity of said rods.

10. Apparatus of the class described comprising a pair of relatively movable cooperating jaw members, power operated means to move said jaw members into and out of engagement with each other, an electrode swingably mounted on one of said jaw members so that it may be swung from a position at one side of said iaw member to a position between said jaw members, means to maintain said electrode in its position between said jaw members when said jaw members are separated and to swing said electrodeto its position at the side of said Jaw member when said jaw members are moved towards each other, means to create an electric field in the vicinity of said electrode, and means to cause said power operated means to move said jaw members out of engagement with each other when a body of a predetermined nature passes into said electric field and to move said jaw members into engagement with each other when said body passes out of said electric field.

11. Apparatus of the class described comprising a movable jaw member having a plurality of operating positions, a second jaw member coacting therewith, power operated means to move said movable jaw member from one of said positions to another, an electrode, means to position said electrode in spaced relation to said movable jaw member, means to move said electrode from one side of said movable jaw member to another when said jaw member is moved, a balanced electrical control circuit having two conditions of balance including means to cause said circuit to change from one condition of balance to the other when a body of a predetermined nature passes into and out of the vicinity of said electrode, and electrically operated means con-' trolled by the control circuit and operable to control the operation of said power operated means to move said jaw member in one direction when said circuit is in one condition of balance and to move said jaw member in another direction when said circuit is in the other condition of balance.

12. A textile press comprising relatively cooperating Jaw members having an open and a closed position, power operated means to relativeiy move said members from one position to another, an electrode mounted adjacent said jaw members, said electrode having an alterable capacity to ground, an oscillating circuit, means to cause said circuit to maintain sustained oscillations at a predetermined frequency when said alterable capacity to ground of said electrode is below a predetermined value and to stop the oscillations in said circuit when said capacity to ground is above a predetermined value, means to amplify oscillations produced in said oscillating circuit, means to utilize said amplified oscillations to operate said power operated means, and means to prevent losses from said amplifying means from being reflected into said oscillating circuit.

13. A textile press comprising relative cooperating jaw members having an open and a closed position, motor operated means to relatively move said jaw members from one position to another, an electrode positioned in the vicinity of said jaw members and having an alterable capacity to ground, an oscillating circuit, means to maintain sustained oscillations in said circuit when said capacity to ground of said electrode is below a predetermined value and to stop the oscillations in said circuit when said capacity to ground of said electrode is raised above a predetermined value, an amplifier tube having an input circuit and an output circuit, means to loosely couple said input circuit to said oscillating circuit, a tank circuit in said output circuit, a relay, means to cause oscillations in said tank circuit to energize said relay, and means to cause energization of said relay to operate said power operating means.

- GEORGE C. DEVOL, Ja.

EDWARD M. PRITCHARD. ELBERT W. SHERMAN. 

